Off-highway trucks and associated truck bodies are typically used in quarries, steel mills, power plants, mines, and landfills. Off-highway trucks with carrying capacities of four hundred (400) tons and greater are commonly used for hauling a variety of materials in various off-road hauling environments. As the generic name implies, “off-highway” vehicles/trucks are limited to private, off-highway road use and are typically used in mining or heavy-material haulage environments.
Typically, these off-highway vehicles operate on unpaved gravel or aggregate roads of varying quality. Moreover, with specific regard to mining operations, as these operations advance, new temporary roads are continually being constructed and old roads abandoned. Thus, such ‘mine’ roads can be undulating and at times have extremely soft/poor under footing, which can cause the off-highway trucks operating on these roads to twist or turn at times racking their very frames and the truck bodies sitting on these truck chassis.
The manufacturers of such off-highway trucks generally supply a generic-type, one basic style with minor variations fits all, truck body. While the manufacturer may offer some truck body options, such as body liner plates, floor body rear extensions, or body sidewall extensions, the truck bodies all typically have the same ‘assembly line’ body floor underpinnings. It is rare that this ‘generic’ body approach ever incorporates different body floor underpinnings or structural components that are dependent on the operating conditions that are specific to the location where the truck body is finally being employed or used.
On large off-highway trucks of this size (i.e., up to four hundred (400) ton payload capacity), it is the truck body floors and particularly the body floor substructures that can, over time, be damaged to the point of needing a complete and total repair or rebuild of the typical body floor.
A typical off-highway truck body consists of:                1, the truck body floor, which provides the “foundation” of the truck body;        2. the truck body sides;        3. the truck body front wall or slope; and, optionally,        4. the truck body tailgate, which provides a fourth side of the truck body.        
In practice, of the four components of an off-highway truck body, it is the truck body floor—the “foundation” of the truck body—that is subjected over time to extreme loading impacts. While the truck body sidewalls and front wall are occasionally impacted, these impacts are typically of a material rolling nature against the sidewalls and front wall. In contrast, the truck body floor is continually being impacted by material dropping vertically onto it. Further, while there may be some damage to the sidewalk and front wall caused by loading equipment, any such damage is normally easily repaired. Truck body floors, however, are subjected to a continuous “drop balling” impact that is similar to when drop balls are used to destroy buildings and other large structures.
Typically, when an off-highway truck body reaches the point in its service life where it must be removed from service for a repair or rebuild as a result of this “drop balling,” it is normally because the off-highway truck body floor, i.e., the “substructure” of the truck body “foundation,” has reached the point of functional obsolesce and could shortly fail completely, if not extensively repaired or rebuilt.